Ae Ran, a mother who is proud of her son, hears the shocking news that Do Hoon, her son who left the military, has developed schizophrenia. Afraid of losing her perfect daily life, Ae Ran decides to hide her son's illness. Ae Ran's secret life seems to be smooth but starts to change when Kyeong Hwa, the only person who knows her secret, appears, gradually turning her anxiety into madness.